This invention relates to a photoelectric switch structure for mounting and fixing the light projecting part and the light receiving part of a photoelectric switch into a hole which is perforated in a planar or hollow cylindrical support.
In a typical example of the photoelectric switch which detects the presence of a man or a body, a light projecting part 1a and a light receiving part 1b are separated from a control part of the photoelectric switch 2 and connected with a lead wire 3 as shown in FIG. 1. A photoelectric switch of this type is used as a safety switch, as shown in FIGS. 2 and 3 where the light projecting part 1a and the light receiving part 1b are mounted on the supports 5a and 5b, respectively, of an automatic door 4 so as to be facing to each other. Interception of the light projected from the light projecting part 1a to the light receiving part 1b is detected so that it is confirmed that neither a person nor a material is near the door, before the door is closed.
The ability to mount the above-mentioned light projecting part 1a and the light receiving part 1b is limited by the fact that the door supports 5a and 5b cannot be manipulated from the rear side and that the thickness of the door supports 5a and 5b are different for each use.
Therefore, the light projecting element la' or the light receiving element 1b' has been built in a cylindrical holder 6 shown in FIG. 4, constituting the light projecting part 1a or the light receiving part 1b. The cylindrical part 6b of the holder 6 is inserted into a mounting hole 7 which is provided in the door supports 5a and 5b. The light projecting part 1a and the light receiving part 1b are fixed to the door supports 5a and 5b by screws 8,8 through holes 6c,6c perforated in a flange 6a.
However, because the above mounting structure requires the formation of screw holes 9,9 in the door supports 5a and 5b and the screw-down operation, the mounting work becomes troublesome. Furthermore, the flange 6a has a diameter much larger than that of a lens which is far from the light projecting part 1a or the light receiving part 1b. The exposed state of the flange and the heads 8',8' of mounting screws 8,8 disturbs the outside view.